In devices (referred to as host devices below) that control digital data such as a digital camera, movie, and portable music player, there is a memory card, as a storage device for retaining digital information, mounting a non-volatile memory. In order to realize compatibility between memory cards manufactured by multiple makers and host devices, a scheme for the host device to access a memory card is standardized. A version of the standard is upgraded along with enlargement of capacity and addition of functions of a memory card. A method for making a host device to execute access by showing different storage capacities to each host device with use of multiple ways of capacity reference is proposed (for example, see Patent document 1).    Patent document 1: Unexamined Patent Publication 2004-86505.